<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>01_边框圆角</title>
    <style>
        div {
            width: 400px;
            height: 400px;
            border: 2px solid black;
            margin: 0 auto;

            /* border-radius: 200px; */
            /* border-radius: 50%; */

            /* border-top-left-radius: 100px; */
            /* border-top-right-radius: 50px; */
            /* border-bottom-right-radius: 20px; */
            /* border-bottom-left-radius: 10px; */

            /* border-top-left-radius: 100px 50px; */
            /* border-top-right-radius: 50px 20px; */
            /* border-bottom-right-radius: 20px 10px; */
            /* border-bottom-left-radius: 10px 5px; */

            border-radius:100px 50px 20px 10px / 50px 20px 10px 5px;

        }
    </style>
</head>
<body>
    <div></div>
</body>
</html>